Most of the time, the Magic game uses only positive numbers and zero. You can't choose a negative number, deal negative damage, gain negative life, and so on. However, it's possible for a game value, such as a creature's power, to be less than zero. If a calculation or comparison needs to use a negative value, it does so. If a calculation that would determine the result of an effect yields a negative number, zero is used instead, unless that effect sets a player's life total to a specific value, doubles a player's life total, sets a creature's power or toughness to a specific value, or otherwise modifies a creature's power or toughness.

Example: If a 3/4 creature gets -5/-0, it's a -2/4 creature. It doesn't assign damage in combat. Its total power and toughness is 2. You'd have to give it +3/+0 to raise its power to 1.

Example: Viridian Joiner is a 1/2 creature with the ability "{T}: Add to your mana pool an amount of {G} equal to Viridian Joiner's power." An effect gives it -2/-0, then its ability is activated. The ability adds no mana to your mana pool.

Most of the time, the Magic game uses only positive numbers and zero. You can't choose a negative number, deal negative damage, gain negative life, and so on. However, it's possible for a game value, such as a creature's power, to be less than zero. If a calculation or comparison needs to use a negative value, it does so. If a calculation that would determine the result of an effect yields a negative number, zero is used instead, unless that effect sets a player's life total to a specific value, doubles a player's life total, or sets a creature's power or toughness to a specific value.

Example: If a 3/4 creature gets -5/-0, it's a -2/4 creature. It doesn't assign damage in combat. Its total power and toughness is 2. You'd have to give it +3/+0 to raise its power to 1.

Example: Viridian Joiner is a 1/2 creature with the ability "{T}: Add to your mana pool an amount of {G} equal to Viridian Joiner's power." An effect gives it -2/-0, then its ability is activated. The ability adds no mana to your mana pool.

Example: Chameleon Colossus is a 4/4 creature with the ability "{2}{G}{G}: Chameleon Colossus gets +X/+X until end of turn, where X is its power." An effect gives it -6/-0, then its ability is activated. It remains a -2/4 creature. It doesn't become -4/2.

Planeswalkers have their own unique set of subtypes; these subtypes are called planeswalker types. The planeswalker types are Ajani, Arlinn, Ashiok, Bolas, Chandra, Dack, Daretti, Domri, Dovin, Elspeth, Freyalise, Garruk, Gideon, Jace, Karn, Kaya, Kiora, Koth, Liliana, Nahiri, Narset, Nissa, Nixilis, Ral, Saheeli, Sarkhan, Sorin, Tamiyo, Teferi, Tezzeret, Tibalt, Ugin, Venser, Vraska, and Xenagos. If a player controls two or more planeswalkers that share a planeswalker type, that player chooses one of them, and the rest are put into their owners' graveyards. This "planeswalker uniqueness rule" is a state-based action. See rule 704.

Planeswalkers have their own unique set of subtypes; these subtypes are called planeswalker types. The planeswalker types are Ajani, Arlinn, Ashiok, Bolas, Chandra, Dack, Daretti, Domri, Dovin, Elspeth, Freyalise, Garruk, Gideon, Jace, Karn, Kaya, Kiora, Koth, Liliana, Nahiri, Narset, Nissa, Nixilis, Ral, Saheeli, Samut, Sarkhan, Sorin, Tamiyo, Teferi, Tezzeret, Tibalt, Ugin, Venser, Vraska, and Xenagos. If a player controls two or more planeswalkers that share a planeswalker type, that player chooses one of them, and the rest are put into their owners' graveyards. This "planeswalker uniqueness rule" is a state-based action. See rule 704.

Some prevention effects generated by static abilities refer to a specific amount of damage—for example, "If a source would deal damage to you, prevent 1 of that damage." Such an effect prevents only the indicated amount of damage in any applicable damage event at any given time. It will apply separately to damage from other applicable events that would happen at the same time, or at a different time.

Example: Daunting Defender says "If a source would deal damage to a Cleric creature you control, prevent 1 of that damage." Pyroclasm says "Pyroclasm deals 2 damage to each creature." Pyroclasm will deal 1 damage to each Cleric creature controlled by Daunting Defender's controller. It will deal 2 damage to each other creature that player controls.

Some prevention effects generated by static abilities refer to a specific amount of damage—for example, "If a source would deal damage to you, prevent 1 of that damage." Such an effect prevents only the indicated amount of damage in any applicable damage event at any given time. It will apply separately to damage from other applicable events that would happen at the same time, or at a different time.

Example: Daunting Defender says "If a source would deal damage to a Cleric creature you control, prevent 1 of that damage." Pyroclasm says "Pyroclasm deals 2 damage to each creature." Pyroclasm will deal 1 damage to each Cleric creature controlled by Daunting Defender's controller. It will deal 2 damage to each other creature that player controls.

Some prevention effects prevent the next N damage that would be dealt to each of a number of untargeted creatures. Such an effect creates a prevention shield for each applicable creature when the spell or ability that generates that effect resolves.

Example: Wojek Apothecary has an ability that says "{T}: Prevent the next 1 damage that would be dealt to target creature and each other creature that shares a color with it this turn." When the ability resolves, it gives the target creature and each other creature on the battlefield that shares a color with it at that time a shield preventing the next 1 damage that would be dealt to it. Changing creatures' colors after the ability resolves doesn't add or remove shields, and creatures that enter the battlefield later in the turn don't get the shield.

Some prevention effects prevent the next N damage that would be dealt to each of a number of untargeted creatures. Such an effect creates a prevention shield for each applicable creature when the spell or ability that generates that effect resolves.

Example: Wojek Apothecary has an ability that says "{T}: Prevent the next 1 damage that would be dealt to target creature and each other creature that shares a color with it this turn." When the ability resolves, it gives the target creature and each other creature on the battlefield that shares a color with it at that time a shield preventing the next 1 damage that would be dealt to it. Changing creatures' colors after the ability resolves doesn't add or remove shields, and creatures that enter the battlefield later in the turn don't get the shield.

Some effects state that damage "can't be prevented." If unpreventable damage would be dealt, any applicable prevention effects are still applied to it. Those effects won't prevent any damage, but any additional effects they have will take place. Existing damage prevention shields won't be reduced by damage that can't be prevented.

Some effects state that damage "can't be prevented." If unpreventable damage would be dealt, any applicable prevention effects are still applied to it. Those effects won't prevent any damage, but any additional effects they have will take place. Existing damage prevention shields won't be reduced by damage that can't be prevented.

A prevention effect is applied to any particular unpreventable damage event just once. It won't invoke itself repeatedly trying to prevent that damage.

A prevention effect is applied to any particular unpreventable damage event just once. It won't invoke itself repeatedly trying to prevent that damage.

Some triggered abilities trigger when damage that would be dealt is prevented. Such an ability triggers each time a prevention effect is applied to one or more simultaneous damage events and prevents some or all of that damage.

Some triggered abilities trigger when damage that would be dealt is prevented. Such an ability triggers each time a prevention effect is applied to one or more simultaneous damage events and prevents some or all of that damage.

Exile every object on the stack, including the object that's resolving. Remove all creatures and planeswalkers (including those that are phased out) from combat. All objects not on the battlefield or in the command zone that aren't represented by cards will cease to exist the next time state-based actions are checked (see rule 704, "State-Based Actions").

Exile every object on the stack, including the object that's resolving. Remove all creatures and planeswalkers from combat. All objects not on the battlefield or in the command zone that aren't represented by cards will cease to exist the next time state-based actions are checked (see rule 704, "State-Based Actions").

If an effect gives a player an extra turn or adds a phase or step to that player's turn, that player's team takes the extra turn, phase, or step. If an effect causes a player to skip a step, phase, or turn, that player's team does so. If a single effect causes more than one player on the same team to add or skip the same step, phase, or turn, that team adds or skips only that step, phase, or turn. If an effect causes a player to control another player, the controller of that effect controls the affected player's team.

If an effect gives a player an extra turn or adds a phase or step to that player's turn, that player's team takes the extra turn, phase, or step. If an effect causes a player to skip a step, phase, or turn, that player's team does so. If a single effect causes more than one player on the same team to add or skip the same step, phase, or turn, that team adds or skips only that step, phase, or turn. If an effect causes a player to control another player, the first player controls the affected player's team.

As the declare blockers step begins, the defending team declares blockers. Creatures controlled by the defending players can block creatures attacking any player on the defending team. The defending team has one combined block, and that set of blocking creatures must be legal as a whole. See rule 509.1.

As the declare blockers step begins, the defending team declares blockers. Creatures controlled by the defending players can block creatures attacking any player on the defending team or attacking a planeswalker controlled by one of those players. The defending team has one combined block, and that set of blocking creatures must be legal as a whole. See rule 509.1.

A keyword action that stops a permanent from untapping during the next uptap step of the player who exerted it. See rule 701.36, "Exert."

A keyword action that stops a permanent from untapping during the next uptap step of the player who exerted it. See rule 701.37, "Exert."